Cold tolerance of potato plants transformed with yeast invertase gene

Abstract

Our study was carried out with potato plants (Solanum tuberosun L.,cv. Désirée) transformed with the yeast invertase gene under the control of the B33 class I patatin promoter and with the proteinase inhibitor II leader peptide sequence providing for the apoplastic enzyme localization (B33-inv plants) and with the plants transformed with the reporter gene encoding bb-glucuronidase under the control of the 35S CaMV promoter (control plants). Exposure to 5°C during 6 days caused an increase in invertase activity and sugar content in B33-inv leaves in comparison with the control plants. Cell membranes of B33-inv plant cells showed greater cold tolerance under low temperature conditions than control plants that was recorded by electrolyte release. We supposed that higher cold tolerance of B33-inv plants was caused by stabilizing effect of sugar on the membranes, because B33-inv plants differ from the control plants in higher invertase activity, induced by expression of yeast invertase gene, and high content of sugars.